Microbiology MCQs
Microbiology MCQs cover bacteriology, virology, mycology, parasitology, and immunology, testing pathogen identification, microbial physiology, and infection control. Ideal for MDCAT, FCPS, NTS, and USMLE preparation, these quizzes boost academic knowledge, clinical skills, and exam success.
Q: The stain most suitable for visualizing bacterial capsules is
A) Acid-fast stain
B) Endospore stain
C) Gram stain
D) Negative stain
✅ Correct Answer: D
Explanation: Negative staining creates a dark background, making the capsule visible as a clear halo around the bacterium.
Q: Virulence factors in bacteria include
A) Mitochondria
B) Adhesins and toxins
C) Ribosomes
D) Peptidoglycan
✅ Correct Answer: B
Explanation: Bacterial virulence is enhanced by factors like adhesins, toxins, and capsules that help evade host defenses.
Q: The portal of entry for most respiratory infections is the
A) Bloodstream
B) Gastrointestinal tract
C) Mucous membranes
D) Skin
✅ Correct Answer: C
Explanation: Pathogens causing respiratory infections typically enter through mucosal surfaces of the nose and throat.
Q: The primary immune cells involved in phagocytosis are
A) Basophils
B) Neutrophils and macrophages
C) Platelets
D) Erythrocytes
✅ Correct Answer: B
Explanation: Neutrophils and macrophages engulf and destroy invading microorganisms during the innate immune response.
Q: Gram-positive cocci arranged in chains are characteristic of
A) Staphylococcus
B) Escherichia
C) Streptococcus
D) Neisseria
✅ Correct Answer: C
Explanation: Streptococcus species appear as chains of spherical cells under the microscope.